# Math Help - Exponents Growth and Decay

1. ## Exponents Growth and Decay

A common inhabitant of human intestines is the bacterium Escherichia coli. A cell of this bacterium in a nutrient-broth medium divides into two cells every 20 minutes. The initial population of a culture is 65 cells.

(a) Find the relative growth rate.
(b) Find an expression for the number of cells after t hours.
(c) Find the number of cells after 6 hours.
(d) Find the rate of growth after 6 hours
(e) When will the population reach 20,000 cells

2. Originally Posted by kashifzaidi
(b) Find an expression for the number of cells after t hours.

$P = 65\times 2^{3t}$

This should help with the rest.